Improvement in air-brake valves



G..WESTING'H0USE.J1-.

yAIR-151mm VALVE. No.172.,064. Patented Jan.11,1a7ve.

l VE lill?.

NFTERS, FMOTOLITHOGRAFNER. WASHINGTON. D. (.V

PATENT Orrcnu GEORGE v,VVES'IINGHOUSE, AJR., vlPIT'ISBURG, PENNSYLVANIA.

IMPRQVEMENT lN AIR-BRAKE VALVES.

Specication forming part of -Letters Patent No. 172,064, dated January11, 1876; application filed December 18, 1875.

To alt whom it may concern Be it known. that I, GEORGE WEs'rING- HOUSE,Jr., of Pittsburg, county of Allegheny, State of Pennsylvania, haveinvented or discovered a new and useful Improvement in Air-Brake Valves;and I do hereby declare the following to be a full, clear, concise, andexact description thereof, reference being had tothe accompanyingdrawing, making a part of this specitication, in which-like lettersindicating like parts- Figure l is a longitudinal sectional view of myimproved valve; and Fig. 2 is a transverse sectional view through theline a: 00 Fig. 1.

My present invention relates to an improvement in the valve devicepatented to me October 5, 1875,7by Patent No. 168,359. It is intendedfor the same purpose as therein set forth, performsthe same function,and includes only such changes in construction and operation ashereinafter set forth.

The valve-case D is the same, inclosng a like piston-chamber, a,valve-chamber, al, and communicating passage a? also the screwcap D',with its air grooves and ports,` and tubular extension d, and stem-guided1; also the stem el, with its collar and spring; also the piston G,with its stem g, valve H, cock B', and the passages and ports which leadfrom and to such valve and cock, and from and to an auxiliary reservoir,brake-cylinder, and brake-pipe.

All these devices, having by the prior patent become a part of the priorstate of the art, need. not here be more fully described.

My present improvement dispenses with the side port s in the`valve-case, and provides for an air-portlherein alsolettered s)directly through the piston G, with one or more lateral ports, s', open54 thence into the passage a2. The end of the port s next thc chamber ais made large enough for the insertion of a stem, c, of a somewhat lessdiameter, such 'stem c being connected by an enlargement,

c', to the end of the stern d4. The smallest part c of this compoundstem is of the diameter of the smaller part of the port s, (orpreferably a little less,) so that as the pistonG makes a downstroke, cwill enter the` smaller part of s, and clean out any dust, dirt, orother obstruction which may have lodged therein.

The enlargement c of the compound stem is .ofsuch length, size, andposition relative to the piston G and the adjacent end of the port sthat when the devices are in the position shown, (the brakes then beingoff and the train in' running condition,) such end of s will be open forthe free passage of air from the brake-pipe to the auxiliary reservoir;but with a diminution of air-pressure in the chamber a the back pressureof air from the auxiliary reservoir will shift the piston G, so that theport s, slipping onto the enlarged part c',

will be closed thereby, andthe escape of air cut off in advance of theopening of the communication from the auxiliary reservoir to thebrakecylinder; and that this may be done without having to overcome anyresistance from the slide-valve H, I make the distance between thecollars c e a little greater then the length of the valve, as shown.

Hence the port s will be closed before the valve H begins to move forapplying the stem, with the operation and result stated in the patentabove cited.

It is not necessaryvthat the ports should be of a reduced size at anypoint, but I prefer to make it as small as practicable for supplying theamount of compressed air desired,

in order that there may be as small an escape as possible when the backpressure on the piston G is brought into effective operation.

I claim herein as my inventionl. The sliding piston G, having anair-port, s, closed and opened by sliding onto and oli' of a stem, c',and in combination therewith, substantially as set forth.

2. The sliding piston G, having an air-port,

s, in combination with the compound stem c In testimony whereof I havehereunto'set and c d, substantiallyas set forth. myh'an'd.

3. The slide-valve H, made shorter than the distance between its endbearings, iu com GEORGE WESTINGHOUSE, JR. bination with the port s' andstem c', relative- 1y arranged with reference to the operationWitnesses:

of the valve H, While the port s is closed,` lsubv JAMES M. CHRISTY,stantially as set forth. GEORGE H. CHRISTY.

